During manufacture, a nonwoven web is generally guided via guide and/or treatment rollers after the plastic fibers have been deposited to form the nonwoven web. The treatment rollers may be, for example, pinch rollers for compacting the nonwoven web or calender rollers for calendering the nonwoven web.
A method and apparatus of the above-described type is known in various embodiments from the prior art. When a nonwoven web is conveyed with a deposition screen belt and/or by guide rollers and/or treatment rollers, a flow of air that moves in the travel direction of the nonwoven web is produced at all times. With respect to the nonwoven webs, this flow of air leads to a poor operational performance, especially in the region of the guide rollers and/or treatment rollers between the deposition screen belt and a windup device. The operational performance is also adversely affected at the deposition screen belt and in the region of the winder. The poor operational performance results in a fluttering of the nonwoven web that may result in tearing or undesired wrinkling in the nonwoven web. Attempts to compensate for these disturbances use higher web tension order to control the nonwoven web. This higher web tension results in turn in a smaller width of the nonwoven web on the winder, as well as deteriorated properties of the nonwoven web, especially a lower resistance or tensile strength of the nonwoven web transversely to the machine direction (in the CD direction). The air entrained by the nonwoven web can also be problematic when the nonwoven web travels around a guide roller and/or a treatment roller. This can lead to an undesired floating of the nonwoven web on the roller; in addition, a flow of air may be directed out from a roller onto the nonwoven web face, causing the product to have undesired non-homogeneous properties.
In order to counter the above-described negative properties, it is already known from the prior art to incorporate additional rollers (guide rollers or deflection rollers) into the conveyance path of the nonwoven web. Other guiding elements, such as curved rods or the like, have also already been used. These measures not only are complex and expensive, but also have often failed to produce the desired results. It is furthermore already known to incorporate so-called spoiler sheets into the conveyance path of the nonwoven web, in order to divert air currents. Here, too, satisfactory results have generally not been achieved thus far.